m-AI Chanukkah

Chanukkah Regex

One problem I like to present to students this time of year is to write a function to match all correct spellings of the word Chanukkah, and mismatching all incorrect spellings.

Something like:

How do we determine if a spelling is accurate? For instance, “Purim” shouldn’t match. “Chanukkah” should match, as should “Hanukah”, but not, IMHO, “Channukah”.

The pedantic reason for this — feel free to skip this paragraph — is that the Hebrew word is spelled חֲנֻכָּה or חֲנוּכָּה. This is: Chet chataf-patach Nun kubutz kaf dagesh-chazak kametz Heh-without-mapik. Each Hebrew glyph has an associated sound and could be transliterated in various valid ways. So ח could be transliterated as H, Ḥ, Ch, or Kh, which thus form a character equivalence class. The chataf-patach vowel develops from a sheva, but a sheva cannot appear after a guttural such as chet, so it gets an “a” sound and transliteration. The נ will be an “n”. There is no dagesh in the נ indicating gemination, that is, doubling of the letter, so it should not be “nn” as some people write, influenced perhaps by the gemination of “k”. There shouldn’t be gemination because that occurs after a short vowel where we need to close the prior syllable and begin the next syllable, but that doesn’t occur by a sheva / chataf-patach. The וּ could be rendered as “u” or “oo”. The כ has a dagesh chazak, which both selects the plosive rather than fricative version — thus “k” rather than “ch” — and geminates it. But gemination is often optional in English spelling, so it will either be '“k” or “kk”. The kametz could be transliterated as “a” or “o”. Ideally, we should be consistent in our transliteration scheme, so if a kametz is transliterated as “a” in one place in the word, it should be transliterated identically elsewhere as well. Finally, the Heh in word-final position could be rendered as either “h” or null.

We might use this to compile, or generate, a regular expression, as follows:

^(Ch|Kh|Ḥ|H)an(u|oo)kk?ah?$

A second approach could be to search StackExchange to see if someone has posed the question and if someone has answered it. Indeed, it is answered on Stack Overflow. The answerer notes various spellings out in the wild, and tries to capture all of them. I frown at some of these spellings, which include a geminated “n”, but this is the difference between a descriptivist and prescriptivist approach. The regex is:

/(Ch|H|Kh)ann?[aeiu]kk?ah?/

but even there, commenters kvetch that the regex is too loose, and will accept invalid strings. Why invalid? Because certain vowels, like “e” for וּ, are only valid in certain pronunciations, which are paired with specific earlier transliteration choices. Perhaps.

A recently popular approach is to ask ChatGPT. So here was my chat:

Joshua Waxman: Please write an English regular expression for the Hebrew word חנוכה, to capture all its correct variant spellings.

ChatGPT: Here is a regular expression that will capture all correct variant spellings of the Hebrew word "חנוכה":

This regular expression uses a combination of literal characters and character classes to match the different possible spellings of the word…

and it continued. This is obviously a bad result, because it didn’t give me something in English, not realizing I wanted transliterations. Also, since it didn’t know the correct nikkud (vowel points), it incorrectly used a full patach under the Chet, incorrectly placed a dagesh chazak inside the Nun, and had Channuchat as an option.

I continued the chat:

Joshua Waxman: No, I want a regular expression for the English transliterations of that Hebrew word. So, for instance, it should match with Chanukka and Chanukah.

ChatGPT: Here is a regular expression that will match English transliterations of the Hebrew word "חנוכה":

This regular expression uses a combination of literal characters and character classes to match different possible transliterations of the word…

and it continued. This was a little bit better, since it encoded two correct spellings, and didn’t geminate the Nun. However, [kah] in the first two examples are a character equivalence class, meaning that the letter that can appear is either k, a, or h. Thus, the first example would accept “Chanukk”, “Chanuka”, or “Chanukh”.

That is unfortunate.

More unfortunate it that people have started using ChatGPT to answer questions on Stack Exchange, according to The Verge and this post on Meta Stack Overflow. As a reaction to the flood of seemingly correct but often incorrect answers, such responses are at least temporarily banned.

This situation is bad for many reasons. Often, people ask questions on Stack Overflow not because they are easy, but because they have tried the straightforward and obvious approach and something is askew. It doesn’t work as it should, because of a bug, or some configuration which is slightly off. “Helpful” confident solutions will waste both moderators’ and questioner’s time.

Secondly, Stack Overflow is surely one of the inputs used to train ChatGPT in the first place. Those were real, often thoughtful responses. Except for the fact that the people behind ChatGPT can detect whether ChatGPT likely generated a piece of text, a decade hence we might end up with garbage ChatGPT output being used to train the next incarnation of ChatGPT. Garbage In, Garbage Out. There is a value in human-crafted responses.